The present invention relates in general to the field of cattle stalls, and in particular to milking parlors and milking stalls designed for compactness, efficient parlor operation, and maximum comfort for the cows.
The milking parlor generally consists of an array of individual stalls, each designed to hold a cow or other dairy animal while she is being milked. An attendant or operator is usually required to be present at the parlor to perform such tasks as ensuring that the animals are properly situated in the stalls; washing the udders prior to milking; applying milker units; and monitoring and attending to the operation of the milking units. The attendant also ensures that the cows to be milked enter the dairy parlor through an entrance gate, and that they exit the dairy parlor through an exit gate when the milking is completed.
A recent development of parlor design is the so called side-by-side or parallel stall configuration. Here, the cow is positioned facing outwardly from the operator and milking takes place at the rear of the cow, that is, between the hind legs. Variations of this design include a V-shaped parlor arrangement and a curved parlor arrangement, the later being discussed in U.S. Pat. No. 5,000,119, having the same assignee as this matter.
These side-by-side parlors are designed so that cows enter through an entry gate into an aisle or pathway along the rear side of the parlor, and then turn approximately 90 degrees and enter the furthest stall that is not yet occupied by a cow. A scheme of sequencing gates can be employed to ensure that the cows proceed to the proper stall.
The milking parlor generally has a rear wall that defines one side of the entry aisle, dividers that serve as side walls, and an exit gate at the front of each stall. The rear wall, which can contain a kick bar and a manure shield, for example, defines the milker position. The cow's hind legs are to be positioned against this wall. The front or exit gate can be of a sideways swinging or race gate design, with doors that swing open to release the cow, or can be of an upward swinging or yoke-type design, which moves upward or above the cow to release her from the stall. The sequencing gate can form a part of the side wall that separates the cows from one another.
The cow stalls have a predetermined length, i.e., between the rear wall and the front gate when the same is in its lowered or closed position. However, the cows are not all of the same predetermined length from hind legs to shoulder. Consequently, an indexing system is desirable for a milking parlor of this type. The term "indexing" simply means adjusting the length of each stall of the milking parlor so that the rear legs of the cow are at the rear wall, that is, at the milker position. Indexing can be carried out by adjusting the stall length, i.e., the distance from the exit gate to the rear kick rail or manure shield, to correspond to the length of the cow in the dairy parlor stall. This can be accomplished by moving the front or exit gates back by means of pneumatic cylinders.
In indexing dairy parlor current systems, gang indexing is most frequently employed. For gang indexing, a single pneumatic cylinder adjusts the position of all of the exit gates of a group of cattle stalls in a milking parlor. Adjusting the gates as a group is considered easier and more cost effective than individual indexing using individual pneumatic cylinders. Fewer pneumatic actuators, fewer controls are required. However, gang indexing is useful only when all of the cows that are being milked at any one time are approximately the same length.
Also, in a pneumatic indexing scheme, in addition to the cylinders required for lifting and lowering the gates to release the cows after milking, an additional set of cylinders is commonly used for indexing. The additional cylinder is needed because pneumatic actuators when used for partial stroke operation require rather complex control equipment such as limit switching and special valves.